Standard Life’s chief executive, Keith Skeoch, said Britain’s EU membership made it easier to sell funds to investors across the region. “It would be in the best interests of customers and clients that we continued to benefit from access to the single market.”

EU summit: 'English lunch' delayed until tea time – live

Read more

He said that, like other financial services firms, the company was drafting contingency plans for a possible Brexit. “It’s deeply, deeply technical stuff that’s associated with the running of our funds.” Skeoch said the firm was able to draw on some of the planning it did 18 months ago in preparation for Greece’s possible exit from the eurozone.

Sir Gerry Grimstone, the chairman, wrote in the company’s annual report: “The principle behind the single market – to encourage the free movement of goods and services – has created an environment that gives individuals and businesses the confidence to invest for the long term and it would be potentially damaging to the UK economy and therefore to companies such as Standard Life if the UK were to leave it.”

Skeoch said uncertainty around the Brexit referendum, which is expected to be held in June, had affected the sterling-dollar exchange rate much more than stock markets, pushing the rate lower to $1.42 on Friday.

The insurance and investment firm shrugged off the recent turmoil on financial markets to post a 9.4% rise in operating profits to £665m, better than expected.

Skeoch said the difficult conditions in global financial markets “may persist for some time”. He said volatility had increased since the start of the millennium, and that the latest bout was a “bit odd” in that it was caused mainly by geopolitical fears, rather than actual changes in the underlying economic conditions.

Brexit featured at the end of a long list of investor concerns, he said – the knock-on effects of China’s economic slowdown; unrest in the Middle East and the refugee crisis; the oil price crash and its impact on inflation; and the question whether the reaction from central banks, with the Bank of Japan moving to negative interest rates, was “fit for purpose”.

But, he added: “Volatility brings its challenges but it also brings its opportunities.” He also highlighted buying opportunities for those investing for the next three to five years.